1. Field of the Invention
The present invention relates to optical fiber technology, and more particularly to a mono-block type mono-block type optical fiber adapter, which comprises an adapter body that comprises a partition wall between each two opposing accommodation chambers and a tubular coupling portion extended from each partition wall toward the inside of one respective front-sided accommodation chamber, a ferrule mounted in each tubular coupling portion and partially suspending in the respective rear-sided accommodation chamber, and a ferrule holder respectively mounted in each rear-sided accommodation chamber and attached to the suspended rear end of the respective ferrule.
2. Description of the Related Art
Following fast development of communication and internet technology, telephone and network facilities are widely used for data transmission and real time communication, bringing great convenience to people. In a communication system, cables are used for transmitting electrical signal or optical signal. The transmission of optical signal is faster than the transmission of electrical signal. Optical fiber cables are commonly used for transmitting optical signal. Further, optical fiber cables have the advantages of strong anti-electromagnetic interference anti-noise ability, wide bandwidth, light weight, long distance transmission and good privacy.
Further, many different types of optical fiber connectors are commercially available. The most widely used optical fiber connectors are SC (subscriber/square/standard) connectors and LC (lucent/local/little) connectors. A LC (lucent/local/little) connector shrinks the size of ferrules to 1.25 mm in diameter with a fiber pitch of 6.25 mm. Two LC simplex connectors can be joined to form a duplex connector. LC optical fiber connectors are low cost, reliable and can be easily installed to terminate fiber optic cables. Further, LC optical fiber connectors provide simplex and duplex transmission flexibility.
Further, mono-block type optical fiber adapters are equipped with ferrules for alignment and connection between mating optical fiber connectors. These ferrules can be made of ceramics or copper, and are adapted to act as alignment mechanisms. They have the advantages of high dimensional precision, high mechanical durability, low insertion loss and low reflective loss, minimizing optical signal loss. As shown in FIG. 12, a conventional optical fiber adapter is a two-piece design, comprising a front shell member A, a rear shell member B, and two ferrules C. The front shell member A and the rear shell member B each comprise two accommodation chambers A1/B1, two side wings A2/B2 respectively bilaterally disposed at the rear side thereof, and two locating holes A11/B11 located on the back wall thereof. The two ferrules C are respectively inserted through the locating holes A11/B11. Further, the front shell member A and the rear shell member B are joined together, and then the side wings A2/B2 are bonded together by ultrasonic welding. During application, optical fiber connectors are respectively mounted in the accommodation chambers A1/B1, and the optical fiber cores of the optical fiber connectors are respectively aligned and connected in the ferrules C for transmitting optical signals.
According to aforesaid prior art design, the front shell member A and the rear shell member B are separately made using different molds. In consequence, the level of inconvenience and difficulty in designing the molds is relatively increased. Further, after the front shell member A and the rear shell member B are attached together, an ultrasonic welding technique shall be employed to bond the side wings A2/B2 together. During installation of this prior art design, dimensional tolerance and clearance problems may occur. Further, this prior art design does not facilitate mass production, resulting in increased labor cost.
FIGS. 13-15 illustrate another two prior art optical fiber adapter designs. According to these two prior art designs, the adapter body (body shell) D of the optical fiber adapter defines therein a plurality of opposing accommodation chambers D1 at two sides, a partition wall D11 in each two opposing accommodation chamber D1, and two tubular coupling portions D12 respectively extended from two opposite sides of each partition wall D11 into the respective opposing accommodation chambers D1 for accommodating one respective ferrule E in an axial accommodation hole D121 in the two tubular coupling portions D12. According to these two prior art designs, the adapter body D is an one-piece member, and the fabrication of the adapter body D eliminates the ultrasonic welding process as employed in the prior art design shown in FIG. 12. Further, each tubular coupling portion D12 has two or three longitudinal crevices D122 that enhance the elastically deformable ability of the respective tubular coupling portion D12 to facilitate installation of the respective ferrule E. However, if the adapter body D is made of metal, the longitudinal crevices D122 cannot significantly enhance the elastically deformable ability of the respective tubular coupling portion D12 to facilitate installation of the respective ferrule E.
Referring to FIGS. 16 and 17, still another prior art design of optical fiber adapter is shown. According to this design, the adapter body of the optical fiber adapter is a two-piece design, comprising a body shell D and a ferrule holder F. The ferrule holder F is mounted in two adjacent accommodation chambers D1 in the front side of the body shell D and fastened to a locating groove D13 inside the body shell D between the two front-sided accommodation chambers D1. Further, two ferrules E are respectively mounted in the two rear-sided accommodation chambers D1 in the rear side of the body shell D and respectively inserted into respective locating tubes F1 of the ferrule holder F. According to this prior art design of optical fiber adapter, the body shell D can be selectively made out of metal or plastics. If the body shell D is made out of metal, the ferrule holder F can conveniently and accurately mounted in the locating groove D13 inside the body shell D. However, if the body shell D is made out of plastics, frequently plugging and unplugging mating optical fiber connectors can cause loosening or displacement of the ferrule holder F, lowering structural stability and optical fiber connector positioning accuracy.
FIGS. 18-20 illustrate still another design of optical fiber adapter according to the prior art. According to this design, the adapter body of the optical fiber adapter is a three-piece device, comprising a body shell D, a ferrule holder F and a cover member G. The ferrule holder F is formed of two abutted plate members, comprising two tubular coupling portions F1 respectively extended from each of the two plate members and respectively suspending in respective accommodation chambers D1 of the body shell D. Further, two ferrules E are respectively positioned in the tubular coupling portions F1 of the abutted plate members and kept in parallel. The ferrule holder F is mounted in a mounting hole D13 on the middle of the body shell D. The cover member G is covered on the body shell D over the ferrule holder F. Further, shutters H are provided in the accommodation chambers D1 of the body shell D corresponding to the ferrules E. According to this design, the ferrule holder F can be vertically conveniently mounted in the mounting hole D13 of the body shell D. Further, the ferrule holder F loading direction is perpendicular to the extending direction of the accommodation chambers D1. Thus, plugging optical fiber connectors into the ferrules E or unplugging optical fiber connectors from the ferrules E does not generate any drag force or pulling force to the ferrule holder F to cause loosening or displacement of the ferrule holder F. However, because this prior art design of optical fiber adapter is formed of multiple component parts, it has a complicated structure that does not facilitate mass production. Further, the installation of this prior art design of optical fiber adapter requires much labor and time.
Therefore, it is desirable to provide an optical fiber adapter that eliminates the drawbacks of the aforesaid various prior art designs.